To study patients documented PCP. In this study we follow patients who have had previously documented PCP and who have successfully completed therapy institution of therapy. The purpose is to evaluate first decrease in pneumocystis burden in the lung and to investigate the inflammatory response on the lung, the immunologic reaction to the lung, the antigenic and antibody response to pneumocystis, and the recovery of human immune deficiency virus in the lung itself, both the macrophages and lymphocytes.